Internal gear pump



Jan. 25, 1944. UNGAR INTERNAL GEAR PUMP Filed Aug. 16, 1939 2 Sheets-Sheet l ATTORN EY INVENTOR GUSTAVE A. UNGAR Jan. 25, 1944. UNGAR INTERNAL GEAR PUMP Filed Aug. 16, 1959 2 Sheets-Sheet 2 INVENTOR GUSTAVE A. UNGAR ATTORN EY Patented Jan. 25, 1944 INTERNAL GEAR PUMP Gustave A. Ungar, Pelliam Manor, N. Y., assignor, by mesne assignments, to Equi-Flow Inc., New York, N. Y., a corporation of New York Application August 16, 1939, Serial No. 290,357

6 Claims.

-This invention relates to pumps (or motors) for fluids, and more particularly to such devices of the internal gear type.

The primary object of my invention is to generally .improve gear pumps of the specified character. A more particular primary object is to make it possible to fix the internal gear, so that it is stationary and becomes, in effect, a part of the casing. With my improved construction, only one rotating shaft is required with appropriate bearings for that shaft.

Other and more specific objects are to protect the pump against unequal expansion when handling liquids of variable temperature; to provide the pump with a built-in relief mechanism for guarding against excess pressure; to so design the pump when desired as to make the same inherently axially balanced; to arrange the pump if desired for equalized or uniform delivery; to provide the discharge portion of the pump with vanes so arranged as to add a centrifugal pump action to the gear pump action; and to provide the intake portion of the pump with helical surfaces or/and blades to aid the desired intake or suction action of the pump;

To the accomplishment of the foregoing, and other more specific objects, which will hereinafter appear, my invention consists in the pump elements and their relation one to the other, as hereinafter are more particulary described in the specification and sought to be defined in the claims. The specification is accompanied by drawings, in which:

Fig. 1 is a transverse section taken through still another modified pump embodying features of my invention, said section being taken in the plane of the line I-I of Fig. 3;

Fig. 2 is another transverse section through the pump, taken in the plane of the line 2-2 of Fig. 3;

Fig. 3 is a longitudinal section through the pump, taken in the plane of the line 3-3 in Figs. 1 and 2;

Fig. 4 is a development of an annular section through the suction disc, and is taken in the plane of the lines 4-4 in Figs. 2 and 3; and

Fig. 5 is an end view of the rotor assembly of the pump.

Referring to the drawings, the pump is an internal gear pump comprising an internal gear G, and a gear P meshing therewith, which gear will, for convenience, be referred to hereinafter as a pinion. In conventional gear pumps, these parts are rotatably mounted on separate shafts, which shafts are offset from one another and must be arranged as overhung shafts with consequent difliculty in providing adequate bearing support. In the present pump, the outer or internal gear G is stationarily mounted and forms, in effect, a part of the casing of the pump. The present pump requires only a single shaft S concentric with gear G, and having an offset or eccentric part E rotatably carrying the pinion P. The shaft S also carries rotatable walls or discs D at opposite'sides of the gears, one of said discs being provided with a suction port, and the other being provided with a discharge port.

As is customary, the gear G is provided with an odd number of teeth, while the pinion P is provided with one less tooth, thus dividing the spaces between the teeth into expanding spaces which may be used for suction, and contracting spaces which are used for compression.

A method of providing for axial balance of the pump is illustrated in the drawings. While only a single pump is employed, the discs on opposite sides are subjected to like pressure. Referring first to Fig. 3, the pump comprises an annular casing I50 closed by end walls I52 and I54, the wall I52 being sealed, while the shaft S projects through the wall I54. Wall I54 is completed by a cap I56, which in turn carries a packing spring I58 bearing against suitable packing I60. The pump comprises a stationary internal gear G received within an annular seat I62 and held against rotation, as by means of bolt I64. The gear may be allowed some axial movement, so as to fioatingly seat itself between the discs, the only requirement being that it be non-rotatable. Shaft S has an eccentric portion E rotatably carrying a pinion P. A suction disc I66 is keyed to shaft S by means of key I68, while a discharge disc I10'is keyed to shaft S by means of a key I12. Suction disc I66 is provided with a suction port I14, best shown in Figs. 2 and 3. The outside of suction disc I66 is exposed to suction space I16, while the pump inlet I18 communicates tangentially with space I16, as is best shown in Fig. 2.

The discharge disc I10 is a double walled disc which discharges at its periphery, rather than at its outer face. In Fig. 3 the double walls are indicated at I and I82, leaving a discharge space I84 therebetween. This communicates with the annular pressure space I86, which in turn leads to discharge outlet I88.

I There is a space I (Fig. 3) in the pump casing outside the outer wall I82 of disc I10, and it will be evident, on reflection, that by subjecting the space I90 to suction, the pump will be axially balanced. The pressure component is axially balanced between the opposed walls I80 and I82 of disc I10, while the suction components are balanced by being applied to the extreme outer ends of the complete rotor assembly. Since the ends rotate within a cylinder of uniform diameter, they are equal in area. The effective vertical components of the inside areas of the walls I80 and I82 are inherently equal, because the opposed walls are on opposite sides of a common chamber.

Space I90 may be connected to the suction passages in any desired manner. In the present case, a counterbalancing port I92 is provided through the pressure disc I10, this port being located on the suction side of the rotor; that is, in communication (through the tooth spaces) with the intake port I14. This will be seen from inspection of Fig. 3, and also from inspection of Fig. 1, in which counter-balancing port I92 is shown in communication with suction port I14. The counterbalancing port I92 passes through a solid part of disc I10, or in other words, it passes through both walls of disc I and is sealed from the space between the walls by means of a connecting or tubular-like wall I. The outside face of pressure disc I10 is intact, except for the counterbalance port I92, this being brought out in Fig. 5.

If desired, the presence of the space I 84, between the walls I80 and I82 of disc I10, may be utilized to apply centrifugal force, or to obtain a centrifugal pump action in addition to the main gear pump action. Referring to Fig. 1, which is a section taken through the space in disc I10, it will be seen that a series of vanes I96 are provided, and that the metal surrounding the passage I92 is also radially sloped to present vanelike surfaces. The result of this construction is that the liquid is smoothly guided and changed in direction from its initial axial movement to the desired radial movement, and its pressure is increased by centrifugal pump action. The outlet I88 is arranged tangentially on the casing, so as to obtain a smooth, eificient flow of liquid without unnecessary abrupt changes in direction and velocity, with resulting turbulence.

A slight pump action may, if desired, be provided at the suction disc I66. Fig. 4 is a development of an annular section taken through the disc on the circle I9-I9 of Fig. 2, and it will be seen that the ends of port I14 are sloped, and

that the port may be provided with one or more blades I98 which are similarly helically sloped. This helps guide the liquid smoothly through the suction port during rotation of the disc, and it further helps produce some, though perhaps not an important amount of, suction or pump action. Here again, the inlet port I18 is preferably tangentially arranged on the casing, so that the liquid entering the casing will flow in a circular path, preparatory to its passage through the rotating suction disc and the rotor assembly of the pump.

Although the present pump is axially balanced, it is preferably provided with an anti-friction thrust bearing 200 at one end. The other end is received in ordinary bearing bushing 202.

It is believed that the construction and principles underlying the same, as well as the operation and many advantages of my improved internal gear pump, will be apparent'from the foregoing detailed description thereof. It will also be apparent that while I have shown and described my invention in a preferred form, many 1. An internal gear pump comprising a casing having end walls, an internal gear non-rotatably mounted in said casing, a shaft carried by said end walls concentrically with said internal gear, discs of equal area secured on said shaft for :0- tation therewith at opposite sides of said internal gear, an eccentric portion on said shaft between said discs, a pinion rotatably mounted on said eccentric portion and meshing with said internal gear as the shaft rotates, a suction port in one of said discs communicating with said meshing gears, an inlet to said casing communicating with said disc and port, a discharge port in the other disc communicating with said meshing gears, and an outlet from said casing communicating with the periphery of said disc, the-discharge disc being a double-walled disc with a space between said walls and with its discharge at the periphery thereof, the walls bounding the space within the discharge disc being of substantially equal effective area, the aforesaid inlet communicating with the outside surface of the discharge disc in order to axially balance the pump.

2. An internal gear pump comprising a casing having end walls, an internal gear non-rotatably mounted in said casing, a shaft carried by said end walls concentrically with said internal gear, discs of equal area secured on said shaft for rotation therewith at opposite sides of said internal gear, an eccentric portion on said shaft between said discs, a pinion rotatably mounted on said eccentric portion and meshing with said internal gear as the shaft rotates, a suction port in one of said discs communicating with said meshing gears, an inlet to said casing communicating with said disc and port, a discharge port in the other disc communicating with said meshing gears, an outlet from said casing communicating with the periphery of said disc, the discharge disc being a double-walled disc with a space between said walls and with its discharge at the periphery thereof, the walls bounding the space within the discharge disc being of substantially equal effective area, and a balance passage through both walls of said discharge disc and sealed from the space therebetween for placing the outside of the discharge disc in communication with the' outside of the suction disc.

3. An internal gear pump comprisnng a casing having end walls, an internal gear non-rotatably mounted in said casing, a shaft carried by said end walls concentrically with said internal gear, discs of equal area secured on said shaft for rotation therewith at opposite sides of said internal gear; an eccentric portion on said shaft between said discs, a pinion rotatably mounted on said eccentric portion and meshing with said internal gear as the shaft rotates, a suction port in one of said discs communicating with said meshmg gears, an inlet to said casing communicating with said disc and port, a discharge port in the other disc communicating with said meshing gears, an outlet from said casing communicating with the periphery of said disc, the discharge disc being a double-walled disc with its discharge at the periphery thereof, the walls bounding the space within the discharge disc being of substantially equal elfective area, the aforesaid inlet communicating with the outside surface of the discharge disc in order to axially balance the pump, and impeller vanes between the walls of said discharge disc.

4. An internal gear pump comprising a casing having end walls, an internal gear non-rotatably mounted in said casing, a shaft carried by said end walls concentrically with said internal gear, discs of equal area secured on said shaft for rotation therewith at opposite sides of said internal gear, an eccentric portion on said shaft between said discs, a pinion rotatably mounted on said eccentric portion and meshing with said internal gear as the shaft rotates, a suction port in one of said discs communicating with said meshing gears, an inlet to said casing communicating with said disc and port, a discharge port in the other disc communicating with said meshing gears, an

outlet from said casing communicating with the periphery of said disc, the discharge disc being a double-walled disc with its discharge at the periphery thereof, the walls bounding the space within the discharge disc being of substantially equal effective area, a balance passage through both walls of said discharge disc and sealed from the space therebetween for placing the outside of the discharge disc in communication with the outside of the suction disc, and impeller vanes between the walls of said discharge disc for adding a centrifugal pump action to the gear pump action.

5. An internal gear pump comprising a casing having end walls, an internal gear non-rotatably mounted in said casing, a shaft carried by said end walls concentrically with said internal gear, discs of equal area secured on said shaft for rotation therewith at opposite sides of said internal gear, an eccentric portion on said shaft between said discs, a pinion rotatably mounted on said eccentric portion and meshing with said internal gear as the shaft rotates, a suction port in one of said discs communicating with said meshing gears, an inlet with said disc and port, a discharge port in the to said casing communicating other disc communicating with said meshing gears, an outlet from said casing communicating with the periphery of said disc, the discharge disc being a. double-walled disc with a space between said walls and with its discharge at the periphery thereof, the walls bounding the space within the discharge disc being of substantially equal effective area, the inlet communicating with the outside of the discharge disc in order to axially balance the pump, the walls of the suction port being helically sloped and the suction port being provided with a helical blade to facilitate the suction and delivery of fluid to the pump.

6. An internal gear pump comprising a casing having end walls, an internal gear non-rotatably mounted in said casing, a shaft carried by said end walls concentrically with said internal gear, discs of equal area secured on said shaft for rotation therewith at opposite sides of said internal gear, an eccentric portion on said shaft between said discs, a pinion rotatably mounted on said eccentric portion and meshing with said internal gear as the shaft rotates, a suction port in one of said discs communicating with said meshing gears, an inlet to said casing communicating with said disc and port, a discharge port in the other disc communicating with said meshing gears, an outlet from said casing communicating with the periphery of said disc, the discharge disc being a double-walled disc with its discharge at the periphery thereof, the walls bounding the space within the discharge disc being of substantially equal effective area, the inlet communicating with the outside of the discharge disc in order to axially balance the pump, and impeller vanes between the walls of said discharge disc for adding a centrifugal pump action to the gear pump action, the walls of the suction port being hellcally slopedand the suction port being provided with a helical blade to facilitate the suction and delivery of fluid to the pump.

GUSTAVE A. UNGAR. 

